Added max/min/unit - Jake please correct (added these for testing value editing)
Removed method from dataset interface
Fixed bugs in iterator for single value datasets and switching between
long and double outputs
Restricted fill method to provide single items and used set slice
instead for broadcasted replacements
Ensured broadcasted set slice works for compound and complex datasets
Added ability to use single-valued datasets in utility methods
Used a dataset for storing squared errors. The dataset can be
broadcasted.